commit 35b1cb677b6db60e48c4aec18b5649082152afd9
author Mads Ager <ager@google.com> Tue May 30 12:04:11 2017 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Tue May 30 12:04:11 2017 +0000
tree 4f2da7044b034c73fc9547d1400e6667c84b8c0a
parent dd4eb74d2436a8c42faf87fcaefc91eacd864869
parent 60deccbafafd14c1a0b31a64fede1339f017c062

Merge "Tweak handling of arguments when argument register reuse is disabled."

src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java

diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
index f621c67..7103abe 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
@@ -555,7 +555,17 @@
         if (argumentInterval.getUses().size() > 1) {
           LiveIntervalsUse use = argumentInterval.firstUseWithConstraint();
           if (use != null) {
-            LiveIntervals split = argumentInterval.splitBefore(use.getPosition());
+            LiveIntervals split;
+            if (argumentInterval.getUses().size() == 2) {
+              // If there is only one real use (definition plus one real use), split before
+              // that one use.
+              split = argumentInterval.splitBefore(use.getPosition());
+            } else {
+              // If there are multiple real users, split right after the definition to make it
+              // more likely that arguments get in usable registers from the start.
+              split = argumentInterval
+                  .splitBefore(argumentInterval.getValue().definition.getNumber() + 1);
+            }
             unhandled.add(split);
           }
         }